Picture in picture and play in background would be huge for mobile

zap stream is the future.

Would be cool if in the future while streaming you could invite one of your viewers into your stream so you can talk to him via microphone and everyone is listening and watching.

I think twitch tried to implement something like this called "invite guests" buts it's complicated to setup so it's not used much by steamers. Sounds difficut to setup but would be cool.